def example5():
"""
Example 5: Get Elements by Node ID - Level 2
"""
# this example will demonstate:
# - getting the list of elements that share a certain node
# our model
import pyNastran
pkg_path = pyNastran.__path__[0]
test_path = os.path.join(pkg_path, '..', 'models', 'solid_bending')
bdf_filename = os.path.join(test_path, 'solid_bending.bdf')
# instantiate the model
from pyNastran.bdf.bdf import BDF
model = BDF()
model.read_bdf(bdf_filename, xref=True)
f = open('junk.out', 'w')
# given a Node, get the Elements Attached to that Node
# assume node 55
# doesnt support 0d/1d elements yet
nid_to_eids_map = model.get_node_id_to_element_ids_map()
eids = nid_to_eids_map[55]
# convert to elements instead of element IDs
elements = []
for eid in eids:
elements.append(model.Element(eid))
print("eids = %s" % eids)
print("elements =\n %s" % elements)
def cross_reference(self, model: BDF) -> None:
"""
Cross links the card so referenced cards can be extracted directly
Parameters
----------
model : BDF()
the BDF object
"""
msg = ', which is required by QBDY2 sid=%s' % self.sid
self.eid_ref = model.Element(self.eid, msg=msg)
def cross_reference(self, model: BDF) -> None:
"""
Cross links the card so referenced cards can be extracted directly
Parameters
----------
model : BDF()
the BDF object
"""
msg = ', which is required by QBDY3 sid=%s' % self.sid
eids = []
for eid in self.eids:
eids.append(model.Element(eid, msg=msg))
self.eids_ref = eids
def cross_reference(self, model: BDF) -> None:
"""
Cross links the card so referenced cards can be extracted directly
Parameters
----------
model : BDF()
the BDF object
"""
msg = ', which is required by RADBC pid=%s' % self.nodamb
elems = []
for eid in self.eids:
elem = model.Element(eid, msg=msg)
elems.append(elem)
self.eids_ref = elems
def test_cbeam_05(self):
# modification of test_pbeam_05
model = BDF(debug=False)
lines = [
'PBEAM,3,6,2.9,3.5,5.97,0.4,3.14',
' , , ,2.0,-4.0',
]
card = model.add_card(lines, 'PBEAM', is_list=False)
lines = [
'CBEAM 10 3 1 2 0.01.000000 0.0'
]
model.add_card(lines, 'CBEAM', is_list=False)
lines = ['MAT1, 6, 1.0e7,,0.3']
model.add_card(lines, 'MAT1', is_list=False)
lines = ['GRID,1,,0.,0.,0.']
model.add_card(lines, 'GRID', is_list=False)
lines = ['GRID,2,,0.,0.,0.']
model.add_card(lines, 'GRID', is_list=False)
model.cross_reference()
cbeam = model.Element(10)
#cbeam = model.elements[10]
#print("Area = ", cbeam.Area())
#print("I11 = ", cbeam.I11())
#print("I22 = ", cbeam.I22())
#print("I12 = ", cbeam.I12())
#print("J = ", cbeam.J())
#print("Area = ", cbeam.Area())
#print("I11 = ", cbeam.I1())
#print("I22 = ", cbeam.I2())
#print("I12 = ", cbeam.I12())
#print("J = ", cbeam.J())
node_ids = cbeam.node_ids
assert node_ids == [1, 2], node_ids
self.assertEqual(cbeam.Area(), 2.9)
self.assertEqual(cbeam.I11(), 3.5)
self.assertEqual(cbeam.I22(), 5.97)
self.assertEqual(cbeam.I12(), 0.4)
self.assertEqual(cbeam.J(), 3.14)
def test_cbeam_01(self):
"""modification of test_pbeam_05"""
model = BDF(debug=False)
lines = [
'PBEAM,3,6,2.9,3.5,5.97,0.4,3.14',
' , , ,2.0,-4.0',
]
model.add_card(lines, 'PBEAM', is_list=False)
lines = [
'CBEAM 10 3 1 2 0.01.000000 0.0'
]
model.add_card(lines, 'CBEAM', is_list=False)
mid = 6
E = 1.0e7
G = None
nu = 0.3
model.add_mat1(mid, E, G, nu)
model.add_grid(1, [0., 0., 0.])
model.add_grid(2, [0., 0., 0.])
model.cross_reference()
cbeam = model.Element(10)
#cbeam = model.elements[10]
#print("Area = ", cbeam.Area())
#print("I11 = ", cbeam.I11())
#print("I22 = ", cbeam.I22())
#print("I12 = ", cbeam.I12())
#print("J = ", cbeam.J())
#print("Area = ", cbeam.Area())
#print("I11 = ", cbeam.I1())
#print("I22 = ", cbeam.I2())
#print("I12 = ", cbeam.I12())
print("J = ", cbeam.J())
node_ids = cbeam.node_ids
assert node_ids == [1, 2], node_ids
self.assertEqual(cbeam.Area(), 2.9)
self.assertEqual(cbeam.I11(), 3.5)
self.assertEqual(cbeam.I22(), 5.97)
self.assertEqual(cbeam.I12(), 0.4)
self.assertEqual(cbeam.J(), 3.14)
def example7():
"""
Example 7: Get Elements by Material ID - Level 2
"""
# this example will demonstate:
# - getting a list of elements that have a certain material
# our model
import pyNastran
pkg_path = pyNastran.__path__[0]
test_path = os.path.join(pkg_path, '..', 'models', 'sol_101_elements')
bdf_filename = os.path.join(test_path, 'static_solid_shell_bar.bdf')
# instantiate the model
from pyNastran.bdf.bdf import BDF
model = BDF()
model.read_bdf(bdf_filename, xref=True)
f = open('junk.out', 'w')
# assume you want the eids for material 10
pid_to_eids_map = model.get_property_id_to_element_ids_map()
mid_to_pids_map = model.get_material_id_to_property_ids_map()
pids1 = mid_to_pids_map[1]
print('pids1 = %s' % pids1)
## pids1 = [1, 2, 3, 4, 5]
eids = []
for pid in pids1:
eids += pid_to_eids_map[pid]
# convert to elements instead of element IDs
elements = []
for eid in eids:
element = model.Element(eid)
elements.append(element)
print(str(element).rstrip())
def example6():
"""
Example 6: Get Elements by Property ID - Level 2
"""
# this example will demonstate:
# - getting a list of elements that have a certain property
# our model
import pyNastran
pkg_path = pyNastran.__path__[0]
test_path = os.path.join(pkg_path, '..', 'models', 'sol_101_elements')
bdf_filename = os.path.join(test_path, 'static_solid_shell_bar.bdf')
# instantiate the model
from pyNastran.bdf.bdf import BDF
model = BDF()
model.read_bdf(bdf_filename, xref=True)
f = open('junk.out', 'w')
# Creating a List of Elements based on a Property ID
# assume pid=1
pid_to_eids_map = model.get_property_id_to_element_ids_map()
eids4 = pid_to_eids_map[4] # PSHELL
print("eids4 = %s" % eids4)
## eids4 = [6, 7, 8, 9, 10, 11]
# convert to elements instead of element IDs
elements4 = []
for eid in eids4:
elements4.append(model.Element(eid))
# just to verify
elem = model.elements[eids4[0]]
print(elem.pid)
class FEMModel:
"""
Class representing a FEM model which is based on a Nastran bdf file
and which needs to be converted to a Modelica lumped element model.
From the Nastran bdf file only CTRIA3 triangular plate elements, CQUAD4
quadrilateral plate elements and CTETRA four-Sided solid Element are
imported. The corresponding Modelica lumped element models are CTRIA3.mo,
CQUAD4.mo and CTETRA.mo
"""
count = 0 # How many FEMModel objects are there?
def __init__(self, NastranFile, meshfile):
"""
Extend `FEMModel.__init__()` to append required input and output data.
Keyword arguments:
NastranFile -- Nastran input filename
"""
self.NastranFile = NastranFile
self.model = None
self.conv_el = []
self.maxelid = None
self.NCTRIA3 = None
self.NCQUAD4 = None
self.NCTETRA = None
self.NCHEXA8 = None
self.IFdict = {}
self._readNas()
self._getIF()
self.con_mat = np.zeros((self.maxelid, self.maxelid))
self.vol = np.zeros(self.maxelid)
self.F_mat = np.zeros((self.maxelid, self.maxelid))
self.meshfile = meshfile
self.calc_vol()
self.PlatingT = None
print "\nTotal volume of nastran file: %3.3e m^3" % np.sum(self.vol)
FEMModel.count += 1
def _readNas(self):
""" Read the nastran file and extract the elements.
"""
'Create the BDF object'
print "Start reading Nastran file:"
print "%s" % os.path.abspath(self.NastranFile)
self.model = BDF(debug=False)
self.model.read_bdf(self.NastranFile, xref=True)
self.conv_el = [(eid, el)
for (eid, el) in sorted(self.model.elements.items())
if el.type in ['CTRIA3', 'CQUAD4', 'CTETRA', 'CHEXA8']]
self.maxelid = np.max(self.model.element_ids)
self.NCTRIA3 = len([(eid, el) for (eid, el) in self.conv_el
if el.type == 'CTRIA3'])
self.NCQUAD4 = len([(eid, el) for (eid, el) in self.conv_el
if el.type == 'CQUAD4'])
self.NCTETRA = len([(eid, el) for (eid, el) in self.conv_el
if el.type == 'CTETRA'])
self.NCHEXA8 = len([(eid, el) for (eid, el) in self.conv_el
if el.type == 'CHEXA8'])
print '-------------------------------'
print '%-4i elements found in file which can be converted:' % len(
self.conv_el)
print '-------------------------------'
print "%-4i CTRIA3 elements" % self.NCTRIA3
print "%-4i CQUAD4 elements" % self.NCQUAD4
print "%-4i CTETRA elements" % self.NCTETRA
print "%-4i CHEXA8 elements" % self.NCHEXA8
print '-------------------------------'
print "Finished reading Nastran file."
print '-------------------------------\n'
def _getIF(self):
""" Get interfaces.
"""
for spc in self.model.spcs:
for node in self.model.SPC(spc):
s1 = str(node).split("SPC")[1]
nid = int(s1.split()[1])
ngid = s1.split()[3].rstrip('.')
if ngid in self.IFdict:
self.IFdict[ngid]['nodes'].append(nid)
else:
self.IFdict[ngid] = {'nodes': [nid], 'elements': {}}
for key in self.IFdict:
for nid in self.IFdict[key]['nodes']:
tmp = self.model.get_node_id_to_element_ids_map()[nid]
for i in tmp:
inodes = [node.nid for node in self.model.Element(i).nodes]
if np.sum(
[inodes.count(x)
for x in self.IFdict[key]['nodes']]) > 1:
if i not in self.IFdict[key]['elements']:
self.IFdict[key]['elements'].setdefault(i, [])
for eid in self.IFdict[key]['elements']:
el = self.model.Element(eid)
elnodes = [node.nid for node in el.nodes]
if el.type == 'CTRIA3':
sides = [[0, 1], [1, 2], [2, 0]]
if el.type == 'CQUAD4':
sides = [[0, 1], [1, 2], [2, 3], [3, 0]]
for i in range(len(sides)):
v1 = elnodes[sides[i][0]]
v2 = elnodes[sides[i][1]]
if (v1 in self.IFdict[key]['nodes']) and (
v2 in self.IFdict[key]['nodes']):
self.IFdict[key]['elements'][eid].append([[v1, v2], 0])
print self.IFdict
def _connected(self, el_type_1, el_nodes_1, el_type_2, el_nodes_2):
"""
"""
comb = {
'CTRIA3CTRIA3': 2,
'CTRIA3CQUAD4': 2,
'CTRIA3CTETRA': 2,
'CTRIA3CHEXA8': 2,
'CQUAD4CTRIA3': 2,
'CQUAD4CQUAD4': 2,
'CQUAD4CTETRA': 2,
'CQUAD4CHEXA8': 2,
'CTETRACTRIA3': 2,
'CTETRACQUAD4': 2,
'CTETRACTETRA': 3,
'CTETRACHEXA8': -1,
'CHEXA8CTRIA3': 2,
'CHEXA8CQUAD4': 2,
'CHEXA8CTETRA': -1,
'CHEXA8CHEXA8': 4,
}
mask = el_type_1 + el_type_2
inters = len(np.intersect1d(el_nodes_1, el_nodes_2))
if inters == comb[mask]:
value = True
else:
value = False
return value
def _get_con(self):
"""
"""
nid_to_eids_map = self.model.get_node_id_to_element_ids_map()
for (eid, el) in sorted(self.model.elements.items()):
con_el = []
el_type_1 = el.type
el_nodes_1 = el.node_ids
con_el_node = []
for elid in el.node_ids:
[con_el_node.append(i) for i in nid_to_eids_map[elid]]
for eid2 in set(con_el_node):
el_type_2 = self.model.Element(eid2).type
el_nodes_2 = self.model.Element(eid2).node_ids
if self._connected(el_type_1, el_nodes_1, el_type_2,
el_nodes_2):
con_el.append(eid2)
for con in con_el:
self.con_mat[con - 1][eid - 1] = 1
self.con_mat[eid - 1][con - 1] = 1
self.ncon = np.count_nonzero(np.triu(self.con_mat))
print "\nTotal number of internal connections: %i" % (np.count_nonzero(
self.con_mat))
def calc_vol(self):
"""
"""
for (eid, el) in sorted(self.model.elements.items()):
v, lcar = self._calc_el_vol(el, eid)
self.vol[eid - 1] = v
def _calc_el_vol(self, el, eid):
"""
"""
if (el.type == 'CTRIA3') or (el.type == 'CQUAD4'):
a = el.Area()
t = el.Thickness()
v = a * t * 1e-9
lcar = np.sqrt((4. / 3.) * np.sqrt(3.) * (a * 1 / 115.))
if el.type == 'CTETRA':
v = el.Volume() * 1e-9
lcar = (v * 3e6 * np.sqrt(2))**(1. / 3.)
if el.type == 'CHEXA8':
v = el.Volume() * 1e-9
lcar = (v * 1.5e6 * np.sqrt(2))**(1. / 3.)
self.vol[eid - 1] = v
return (v, lcar)
def convert(self, verbose=False, PlatingT=None):
"""
"""
if PlatingT is not None:
self.PlatingT = PlatingT
self.Fpl_mat = np.zeros((self.maxelid, self.maxelid))
print "Adding data for plating thickness of %3.3e" % self.PlatingT
self._get_con()
nF = 0
for (eid1, el1) in self.conv_el:
if eid1:
el1 = self.model.elements[eid1]
(vol, lcar) = self._calc_el_vol(el1, eid1)
print "\nElement %i evaluated: type=%s, lcar=%f, vol=%e" % (
eid1, el1.type, lcar, vol)
points = self.model.elements[eid1].get_node_positions()
if (el1.type == "CTRIA3") or (el1.type == "CQUAD4"):
points = _rotate_2D(points)
if (el1.type == "CTETRA") or (el1.type == "CHEXA8"):
el13d = True
t = None
else:
el13d = False
t = el1.Thickness()
print "Creating mesh..."
mesh_el(el1.type, points, lcar=lcar, filename=self.meshfile)
for eid2 in np.arange(1, self.maxelid + 1):
if eid2:
if self.con_mat[eid1 - 1][eid2 - 1] != 0:
n_ids_1 = self.model.elements[eid1].node_ids
n_ids_2 = self.model.elements[eid2].node_ids
el2 = self.model.elements[eid2]
boundary = np.in1d(n_ids_1, n_ids_2)
if (el2.type == "CTRIA3") or (el2.type
== "CQUAD4"):
el22d = True
else:
el22d = False
if el13d and el22d:
print "3D to 2D connection detected, adjusting boundary."
nodes = []
for node in n_ids_1:
if node not in n_ids_2:
nodes.append(node)
Ftot = 0
for node in nodes:
for i in range(len(boundary)):
if n_ids_1[i] == node:
boundary[i] = True
try:
F = FarField(el1.type,
points,
boundary,
lcar,
0.005,
self.meshfile,
thickness=t,
verbose=verbose)
print "Handling element %i, node %i added, F=%f" % (
eid2, node, F)
Ftot += F
except Exception as e:
print "Handling element %i, F determination failed!" % (
eid2)
print(e)
Favg = Ftot / len(nodes)
self.F_mat[eid1 - 1][eid2 - 1] = Favg
nF += 1
print "Handling element %i, done, Favg=%f" % (
eid2, Favg)
try:
F = FarField(el1.type,
points,
boundary,
lcar,
0.005,
self.meshfile,
thickness=t,
verbose=verbose)
self.F_mat[eid1 - 1][eid2 - 1] = F
nF += 1
print "Step %i, handling element %i, F=%f" % (
nF, eid2, F)
if self.PlatingT is not None:
self.Fpl_mat[eid1 -
1][eid2 -
1] = (self.PlatingT /
t) * F
print "Step %i, handling plating element %i, Fpl=%f" % (
nF, eid2,
self.Fpl_mat[eid1 - 1][eid2 - 1])
except Exception as e:
print "Handling element %i, F determination failed!" % (
eid2)
print(e)
for key in self.IFdict:
if eid1 in self.IFdict[key]['elements']:
IFbound = self.IFdict[key]['elements'][eid1]
for IF in IFbound:
edge = IF[0]
boundary = np.in1d(n_ids_1, edge)
try:
F = FarField(el1.type,
points,
boundary,
lcar,
0.005,
self.meshfile,
thickness=t,
verbose=verbose)
IF[1] = F
print "Handling element %i interface, F=%f" % (
eid1, F)
if self.PlatingT is not None:
IF[2] = (self.PlatingT / t) * F
print "Plating element %i interface, Fpl=%f" % (
eid1, IF[2])
except Exception as e:
print "Handling element %i, interface failed!" % (
eid1)
print(e)
self.vtotal = np.sum(self.vol)
print '\nTotal converted volume: %e\n' % self.vtotal
def ExportModelicaFile(self,
FileName,
WithinStr=None,
MaterialStr=None,
IFnamedict=None,
DiagramStr=None,
PlatingStr=None):
"""
"""
print "Start writing Modelica file:"
print "%s" % os.path.abspath(FileName)
'Open the Modelica file buffer for writing'
f = open(FileName, 'w')
self.modelname = ntpath.basename(FileName)[:-3]
'Write Modelica file header'
if WithinStr is None:
header = "model %s\n" % self.modelname
else:
header = "within %s;\n\n" % WithinStr
header += "model %s\n" % self.modelname
header += " /*\n"
header += " This Modelica file is created using the FarFieldConvert python script.\n"
header += " Nastran input file: %s\n" % os.path.abspath(
self.NastranFile)
header += " Exported on %s, at %s\n" % (
datetime.datetime.now().strftime("%d/%m/%Y"),
datetime.datetime.now().strftime("%H:%M:%S"))
header += " The file Contains the following mesh elements converted into lumped elements:\n"
header += " %-5i CTRIA3 elements\n" % self.NCTRIA3
header += " %-5i CQUAD4 elements\n" % self.NCQUAD4
header += " %-5i CTETRA elements\n" % self.NCTETRA
header += " %-5i CHEXA8 elements\n\n" % self.NCHEXA8
header += " The following %i IF groups were converted from SPC temperature BC's:\n" % len(
self.IFdict)
sortedkeys = sorted(map(int, list(self.IFdict.keys())))
for id in sortedkeys:
key = str(id)
if IFnamedict is None:
header += " %s: %s \n" % (key, str(self.IFdict[key]))
else:
header += " %s: nodes: %s \n" % (IFnamedict[key]['name'],
self.IFdict[key]['nodes'])
if self.PlatingT is not None:
header += " A plating is added to the model with a thickness of %f mm\n" % self.PlatingT
header += " The heat capacity of this plating is neglected, while parallel conductances are added to the base material.\n"
header += " */\n"
f.write(header)
f.write("\n")
'Create material declaration and start temperature statement:'
Strmat = " /* Material declaration: */\n"
if MaterialStr is None:
Strmat += " replaceable package Material = ThermalCryogenics.Materials.Unity\n"
Strmat += " constrainedby Modelica.ThermalCryogenics.Interfaces.PartialMaterial;\n"
else:
if self.PlatingT is None:
Strmat += " replaceable package Material = %s\n" % MaterialStr
Strmat += " constrainedby Modelica.ThermalCryogenics.Interfaces.PartialMaterial;\n"
else:
Strmat += " replaceable package Material = %s\n" % MaterialStr
Strmat += " constrainedby Modelica.ThermalCryogenics.Interfaces.PartialMaterial;\n"
Strmat += " replaceable package Plating = %s\n" % PlatingStr
Strmat += " constrainedby Modelica.ThermalCryogenics.Interfaces.PartialMaterial;\n"
f.write(Strmat)
StrTstart = " parameter Modelica.SIunits.Temperature Tstart(displayUnit=\"K\") \"Start temperature of part\";\n"
f.write(StrTstart)
f.write("\n")
'Create component statements in mo file'
f.write(' /* Component section: */\n')
IFStr = _interfacesection(self, IFnamedict)
f.write(IFStr)
ModelStr = _modelsection(self)
f.write(ModelStr)
'Create connection equations in mo file'
f.write('\n')
self.ConnectStr = _connectsection(self, IFnamedict)
f.write(self.ConnectStr)
'Add footer in mo file'
if DiagramStr is None:
l = len(self.IFdict) * 50.
footer = "\n"
footer += "annotation(Icon(coordinateSystem(initialScale = 0.1),\n"
footer += " graphics={\n"
footer += " Text(\n"
footer += " origin = {0, 0},\n"
footer += " lineColor = {0, 0, 255},\n"
footer += " extent = {{-150, 140}, {150, 100}},\n"
footer += " textString = \"%name\"),\n"
footer += " Rectangle(\n"
footer += " origin = {0, 0},\n"
footer += " extent = {{-100, %.0f}, {100, %.0f}})}),\n" % (
l, -l)
footer += " uses(Modelica(version = \"3.2.2\")));\n"
else:
footer = DiagramStr
footer += "\nend %s;" % self.modelname
f.write(footer)
'Close the mo file buffer'
f.close()
print "Finished"
def cross_reference(self, model: BDF) -> None:
self.eid_ref = model.Element(self.eid)
self.eids_ref = model.Elements(self.eids)
x = float(gpos[0])
y = float(gpos[1])
z = float(gpos[2])
Coord.append(x)
Coord.append(y)
Coord.append(z)
test = points.InsertNextPoint(*Coord)
Color.InsertTuple1(test, 0)
nidMap[nid] = i
i = i + 1
grid.SetPoints(points)
for (eid, element) in model.elements.iteritems():
if isinstance(element, CONM2):
exmcon = model.Element(eid)
val = str(exmcon)
val.strip()
mcon = val.strip().split()
g = (int(mcon[2]))
mconvert = vtk.vtkVertex()
mconvert.GetPointIds().SetId(0, nidMap[g])
Mconcell = grid.InsertNextCell(mconvert.GetCellType(),
mconvert.GetPointIds())
Color.InsertTuple1(Mconcell, 1)
k = 0
for (eid, element) in model.elements.iteritems():
EidMap[eid] = k
if isinstance(element, CBUSH) or isinstance(element, CBEAM):
exbar = model.Element(eid)
